Soil Grain Research Articles

Long-term evaluation of surface topographic and topsoil grain composition changes in an agricultural landscape

Understanding long-term changes in topography and topsoil grain composition is crucial for the management of agricultural landscapes, especially in areas prone to wind erosion. This study investigates long-term changes in topography and topsoil grain composition within an agricultural landscape in south-western Slovakia. To analyse topographic changes over time, we used high-precision positioning measurements and airborne laser scanning to create digital terrain models (DTM) for the years 2011, 2017 and 2020. To assess changes in soil grain composition, we performed grain size analyses on soil samples collected during three different periods: M1 (1961–1970), M2 (2009–2015) and M3 (2015–2016). Changes in soil texture were evaluated to understand the impact of wind erosion on soil composition. The influence of windbreaks was also analysed by comparing the accumulation and deflation processes. The results showed significant changes in both topography and soil texture over the study period. The DTMs showed marked differences in the accumulation and deflation processes, highlighting areas affected by wind erosion. Comparisons of soil samples showed a shift in dominant soil types from loam and clay loam to silty loam, highlighting the effects of wind erosion. Analysis revealed a decrease in clay and silt content and an increase in sand content, indicating wind-induced soil degradation. The presence of windbreaks played a crucial role in reducing soil erosion by reducing wind speed, promoting soil accumulation and stabilising the landscape up to 80 m windward and 20 m leeward. The study highlights the complex interplay of climate and wind factors in shaping topography and soil properties and emphasises the protective role of windbreaks in agricultural landscapes over time. Our results show that wind erosion significantly alters soil texture, which can affect agricultural productivity. However, windbreaks have proven to be an effective measure in reducing soil erosion and maintaining soil quality.

Collapse Pattern in Gypseous Soil using Particle Image Velocimetry

Abstract Gypseous soil is prevalent in arid and semi-arid areas, is from collapsible soil, which contains the mineral gypsum, and has variable properties, including moisture-induced volume changes and solubility. Construction on these soils necessitates meticulous assessment and unique designs due to the possibility of foundation damage from soil collapse. The stability and durability of structures situated on gypseous soils necessitate close collaboration with specialists and careful, methodical preparation. It had not been done to find the pattern of failure in the micromechanical behavior of gypseous sandy soil through particle image velocity (PIV) analysis. This adopted recently in geotechnical engineering to track the motion of soil grains and using tracer particles by applying digital particle image analysis. It has also been used to study the displacement distribution in some cases of granular materials. Therefore, the goal of this study is to find out how gypseous sand medium moves when in contact with a rigid strip foundation that is under static stress and plane strain conditions. The experimental model would focus on two common types of wetting, namely water table rise and dry conditions. The PIV showed that the collapse pattern under the footing is of the type of punching shear failure. The predominant mechanism of soil deformation was the vertical compression of the gypseous granular soil. The results showed that understanding gypseous sandy grain displacement and failure patterns at the local scale is crucial for enhancing the design of foundations under static stress conditions.

Effects of Restricted Irrigation and Straw Mulching on Corn Quality, Soil Enzyme Activity, and Water Use Efficiency in West Ordos

Groundwater overexploitation in West Ordos necessitates sustainable irrigation practices. This study evaluated three irrigation levels—W1 (3300 m3 · ha−1), W2 (2850 m3 · ha−1), and W3 (2400 m3 · ha−1)—by modifying the wide-width planting pattern of maize. Additionally, two levels of straw mulch were analyzed: F1 (9000 kg · ha−1) and F2 (no mulch). The study aimed to investigate the effects of these treatments on corn growth dynamics, soil water temperature, soil enzyme activity, yield, grain quality, and water use efficiency. The results indicated a decline in growth indices, enzyme activities, grain quality, and yield under the limited irrigation levels W2 and W3 compared to W1. The highest corn yields were observed with W1F1 (6642.54 kg · ha−1) and W2F1 (6602.38 kg · ha−1), with the latter showing only a 0.6% decrease. Notably, water use efficiency in the W2F1 treatment improved by 4.69%, 12.08%, 10.27%, 12.59%, and 12.96% compared to W1F1, W3F1, W1F2, W2F2, and W3F2, respectively. Straw mulch (F1) significantly elevated the soil temperature, increasing the effective accumulated temperature during the growth period by 10.11~85.79 °C, and boosted the soil enzyme activity by 10–25%. Under limited irrigation, the W2 (2850 m3 · ha−1) and F1 (9000 kg · ha−1 straw) treatments achieved the highest water productivity of 2.48 kg·m⁻3, maintaining a high yield of 6602.38 kg · ha−1 while preserving nutrients essential to the corn’s quality. This approach presents a viable strategy for wide-width corn planting in groundwater-depleted regions, offering a scientifically grounded and sustainable water management solution for efficient corn production in West Ordos.

Geophysical and Geotechnical Investigation of Building’s Foundation around Crusher area, Lokoja, Kogi state, Nigeria

Integration of geophysical and geotechnical techniques had been utilised to investigate the foundation of a site characterised with building cracks. It was conducted at Muhammadu Buhari Estate, Crusher area in Lokoja, Nigeria, The study aims to delineate geological features responsible for the failure of the building through 2-D resistivity imaging and electromagnetic surveys in conjunction with geotechnical analysis. Seven 2-D electrical resistivity imaging traverse lines, seven electromagnetic profiles were run and seven soil samples were collected and analysed. Each of the sample point were located on each of the 2-D imaging traverse. Traverses 1-7 host samples 1-7 respectively. The findings revealed high conductivity in unstable areas (resistivity ranging from 11-42 Ohm-m, 1-38 Ohm-m, 4-12 Ohm-m, 1-15 Ohm-m, and 11-30 Ohm-m for traverse 1-5, respectively) and low conductivity in stable ones (resistivity ranging from 19-91 Ohm-m and 109-2056 Ohm-m for traverse 6 and 7, respectively) and they occur at near surface to a relatively shallow depths (ranging from 0-6m depth) in all the profile. Geotechnical analysis showed high clay content in the soil, affecting its engineering properties in most of the studied locations. Soil grain oversize data analysis indicated a range between 70.1% and 75.1% for unstable portions (samples 1-5), with an average of 72.22% fines while percentage coarse ranges between 24.9 and 29.9 with an average of 27.78%. Their optimum moisture content ranged from 10.4% to 11.50%, with a mean value of 11.18%. Also, their plastic index averaged at 10.044%, while linear shrinkage varies between 1.79% and 3.60%, with an average of 2.808%. All these are the responsible factors for the soil instability in this axis of the investigated site. But for the stable portions (samples 6 and 7), Soil grain oversize data analysis is between 18.1% and 18.2% with an average of 18.65% fines while percentage coarse range between 81.9 and 80.8 with an average of 81.35%. The optimum moisture content ranged from 10.4% to 11.50%, with a mean value of 11.18%, the optimum moisture content ranged from 11.3% to 12.0%, with a mean of 11.65%, the plastic index equals zero (0), linear shrinkage varies between 5.57% and 5.71%, with an average of 5.64% and all these parameters are responsible for the stability of these two portions. The California Bearing ratio (CBR) results graded the soil samples into different types with the unstable portion characterised with clay, silty clay and sandy clay while the stable portion are classified into well graded sands. The well graded sands are very suitable for the engineering construction and hence the buildings on this portion showed no cracks and failure because of lack of differential settlements unlike that of the unstable portion characterised with cracks due differential settlements that led to structural failure at those sides of the study site. The geophysical results corroborate well with geotechnical results and these highlight the value of combining geophysical and geotechnical techniques to evaluate the integrity of the subsurface, providing information that is essential for designing infrastructure foundations and determining stability.

Tunnel-Shaped Weathering Features in Soil Grains: Why 3D Imaging Must be Performed for Accurate Characterization and Interpretation

Tunnel-Shaped Weathering Features in Soil Grains: Why 3D Imaging Must be Performed for Accurate Characterization and Interpretation

Cadmium Minimization in Grains of Maize and Wheat Grown on Smelting-Impacted Land Ameliorated by Limestone.

Cadmium (Cd) contamination in agricultural soils has emerged as a significant concern, particularly due to its potential impact on plant-based food. Soil pH reductions can exacerbate Cd mobility, leading to excessive accumulation in crops. While liming has been demonstrated as an effective method to mitigate Cd accumulation in rice grains in acid soils of southern China, its efficacy in remediating acid soils in northern China remains unclear. In this study, a multi-year field experiment was conducted on farmland impacted by zinc ore smelting at coordinates of 33.92° N 112.46° E to investigate the use of limestone for controlling Cd accumulation in wheat and maize grains. The results indicated that applying 7.5 t ha-1 of limestone significantly raised the soil pH from 4.5 to 6.8 as anticipated. Different rates of limestone application (2.25, 4.45, and 7.50 t ha-1) reduced Cd bioavailability in the soil by 20-54%, and Cd accumulation in wheat grains by 5-38% and maize grains by 21-63%, without yield penalty. The remediation effects were sustained for at least 27 months, highlighting limestone as a promising ameliorant for smelting-affected farmland in northern China.

Assessing the Impact of Tillage Methods on Soil Moisture Content and Crop Yield in Hungary

A decline in rainfall as a source of agricultural water has affected and will continue to affect sustainable crop production globally including in Hungary. Conservation of the greatest water reservoir is important for the sustainable development of agriculture in Hungary. The objective of this study was to evaluate the effects of the different tillage methods on soil moisture content, grain yield, and root weight of wheat (Triticum aestivum) and sunflower (Helianthus annuus) under rainfed conditions. A field study was conducted at the Józsefmajor Experimental and Training Farm (JM) of the Hungarian University of Agriculture and Life Sciences near Hatvan. The experiment consisted of six tillage treatments: disking (D, 16 cm), shallow cultivation (SC, 20 cm), no-till (NT), deep cultivation (DC, 25 cm), loosening (L, 45 cm), and plowing (P, 30 cm). Soil moisture content (SMC) was measured monthly, and grain yield and root weight were measured at the end of the cropping period. Our results showed no significant difference in SMC between conservation and conventional tillage methods in 2018. However, in 2021, greater SMC was significantly conserved under NT compared to P. Regarding the sampling date, a significant increase in moisture with time was observed. A significantly lower SMC was observed on 3 June 2019 between L and D. while on the 9 September 2020, SMC significantly differed between P and all the other treatments (D, SC, NT, DC, and L). Interestingly in 2018, SMC was significantly lower at 10–20 cm depth between L and D. Notably the effect of depth on SMC was observed as moisture significantly increased with increasing depth in all tillage treatments. Root weight was greatest at DC (1.54 t ha−1) in 2018 and under L (3.89 t ha−1) in 2021. Similarly, wheat grain yield was greatest at DC (2.48 t ha−1) in 2018, while sunflower yield in 2021 was greatest at L (3.86 t ha−1). It is comprehensible that conservation tillage methods such as L and NT can increase SMC and grain yield.

Improving the Estimation Accuracy of Soil Organic Matter Content Based on the Spectral Reflectance from Soils with Different Grain Sizes

Accurate and rapid estimation of soil organic matter (SOM) content is of great significance for advancing precision agriculture. Compared with traditional chemical methods, the hyperspectral estimation is superior in rapidly estimating SOM content. Soil grain size affects soil spectral reflectance, thereby affecting the accuracy of hyperspectral estimation. However, the appropriate soil grain size for the hyperspectral analysis is nearly unknown. This study propose a best hyperspectral estimation method for determining SOM content of farmland soil in the Ibinur Lake Irrigation Area (ILIA) of the northwest arid zones of China. The original spectral reflectance of the 20-mesh (0.85 mm) and 60-mesh (0.25 mm) sieved soil were obtained, and the feature wavebands were selected using five types of spectral transformations. Then, hyperspectral estimation models were constructed based on the partial least squares regression (PLSR), support vector machine (SVM), random forest (RF), and extreme gradient boosting (XGBoost) models. Results show that the SOM content had relatively higher correlation coefficient with spectral reflectance of the 0.85 mm sieved soil than that of the 0.25 mm sieved soil. The transformation of original spectral reflectance of soil effectively enhanced the spectral characteristics related to SOM content. Soil grain size obviously affected spectral reflectance and the accuracy of hyperspectral estimation models. The overall stability and estimation accuracy of RF model was significantly higher compared with the PLSR, SVM, and XGBoost. Finally, the RF model combined with the root mean first-order differentiation (RMSFD) of spectral reflectance of the 0.85 mm sieved soil (R2 = 0.82, RMSE = 2.37, RPD = 2.27) was identified as the best method for estimating SOM content of farmland soil in the ILIA.

Stormwater quality and microbial ecology in an urban rain garden system

Rain gardens are an alternative to traditional drainage, able to lower flood risk and reduce environmental contamination from stormwater. Removal of contaminants by rain gardens is driven by both physical processes (such as filtration and sedimentation) and biological metabolic processes by soil microorganisms. To better understand rain garden performance, this study explored the impact of rain gardens on pollution removal and microbial composition and function using rain gardens fed real stormwater from a busy road. Each rain garden had different grain size and hydraulic conductivities as these parameters have been argued to impact pollution removal. All four rain gardens were able to reduce the contaminant load in the stormwaters, reducing the concentration of dissolved metals, suspended solids and chemical oxygen demand. Significantly, road salting in the winter did not cause dissolved metals to be released from the rain gardens, suggesting that rain gardens can continue to reduce contaminant loads during winter salting regimes. Some variation in pollutant removal was seen between the soils tested, but overall no clear trend could be identified based on grain size and hydraulic conductivity with all rain gardens performing broadly similarly. The rain garden soil altered the microbial community in the stormwater, resulting in greater taxonomic evenness and functional richness in the effluent water compared to the influent. Functional richness of the soils was also higher than that of the input waters, indicating that the microbes in the rain gardens were able to perform a wider range of functions than those of the influent. Effluent and soil microbiology was more impacted by sampling date than soil grain size, which may be a result of the soil communities maturing and changing over time. As greater numbers of rain gardens are installed to tackle flooding from climate change, it is important to ensure the environment is protected from urban contaminants in the stormwater. The results in this study further highlight the ability of rain gardens to undertake this important task.

Green manuring improves soil quality, grain yield, and grain anthocyanin content in colored rice cultivated in tropical regions

AbstractGreen manuring is the process by which vegetative crops are incorporated into the soil, and it plays a good substitutable role in reducing chemical fertilizer applications while enhancing soil fertility. Field experiments were conducted at Lingao City of Hainan Province in 2020 and 2021, to evaluate the effects of in situ incorporation of different green manures (fallow (as control), rice, sesbania, and stylosanthes) on soil physical and chemical properties, nitrogen (N) uptake, grain yield, and the grain anthocyanin content in colored rice. Treatments included colored rice cultivated with previous fallow (T0), with previous rice straw manure (T1), with previous sesbania manure (T2), and with previous stylosanthes manure (T3). The seedlings of the colored rice variety Suixiangheinuo were transplanted 23 days after the incorporation of green manure. Our results indicated that both the grain yield and grain anthocyanin content of colored rice were significantly increased when green manure was incorporated into the soil compared to that of the control. Therein, grain yields of T1, T2, and T3 were increased by an average of 12.7%, 29.0%, and 24.5%, respectively, across 2 years in comparison with those of T0. And grain anthocyanin content in colored rice under T1, T2, and T3 was increased by 7.2%–7.5%, 13.9%–24.2%, and 9.8%–20.6%, respectively. In addition, in situ incorporation of leguminous green manure in the soil significantly increased soil fertility and partial factor productivity for N fertilizer. The above results suggested that colored rice crops should be followed in rotation with leguminous green manure, which was beneficial to increasing both grain yield and grain anthocyanin content of colored rice. This research elucidated that the incorporation of leguminous green manure sustained the production of colored rice in tropical regions, which was beneficial to reconcile the relationship between rice production and environmental protection.

Improving the sustainability of arable cropping systems by modifying root traits: A modelling study for winter wheat

AbstractModifying root systems by crop breeding has been attracting increasing attention as a potentially effective strategy to enhance the sustainability of agriculture by increasing soil organic matter (SOM) stocks and soil quality, whilst maintaining or even improving yields. We used the new soil‐crop model USSF (Uppsala model of Soil Structure and Function) to investigate the potential of this management strategy using winter wheat as a model crop. USSF combines a simple (generic) crop growth model with physics‐based descriptions of soil water flow, water uptake and transpiration by plants. It also includes a model of the interactions between soil structure dynamics and organic matter turnover that considers the effects of physical protection and microbial priming on the decomposition of SOM. The model was first calibrated against field data on soil water contents and both above‐ground and root biomass of winter wheat measured during one growing season in a clay soil in Uppsala, Sweden using the GLUE method to identify five ‘acceptable’ parameter sets. We created four model crops (ideotypes) by modifying root‐related parameters to mimic winter wheat phenotypes with improved root traits. Long‐term (30‐year) simulations of a conventionally tilled monoculture of winter wheat were then performed to evaluate the potential effects of cultivating these ideotypes on the soil water balance, soil organic matter stocks and grain yields. Our results showed that ideotypes with deeper root systems or root systems that are more effective for water uptake increased grain yields by 3% and SOM stocks in the soil profile by ca. 0.4%–0.5% in a 30‐year perspective (as an average of the five parameter sets). An ideotype in which below‐ground allocation of dry matter was increased at the expense of stem growth gave even larger increases in SOM stocks (ca. 1.4%). An ideotype combining all three modifications (deeper and more effective root systems and greater root production) showed even more promising results: compared with the baseline scenario, surface runoff decreased while yields were predicted to increase by ca. 7% and SOM stocks in the soil profile by ca. 2%, which is roughly equivalent to ca. 20% of the 4‐per‐mille target (https://4p1000.org/).

Influence of soil properties on selenium concentration in paddy soil and rice grains in the hilly regions of southern China

BackgroundSelenium (Se) is essential for human health and is predominantly obtained from dietary sources, particularly rice in Hunan Province, a significant rice-producing region in southern China. Investigating the relationship between Se levels in paddy soil and rice grains, along with the associated influencing factors, is critical for enhancing Se-enriched food security.ResultsAnalysis of 128,992 samples collected between 2019 and 2022 revealed that the soil Se concentration in Hunan exceeded the global average, with rice grains showing promising potential for Se enrichment. Various analytical methods, including statistical analyses, co-occurrence networks, and correlation heatmaps, were utilized to scrutinize the extensive dataset. Additionally, partial least squares path analysis elucidated the interactive effects of influencing factors on soil Se concentration, rice grain Se concentration, and Se bioconcentration factor (BCF). Soil parent materials significantly affected soil Se concentration, rice grain Se concentration, and Se BCF (p < 0.01). Factors such as soil cation exchange capacity, soil organic matter, slope, and soil concentrations of Cu, Mn, and Zn demonstrated positive correlations with soil Se concentration. Similarly, these factors exhibited positive associations with rice grain Se concentration. Conversely, negative correlations were observed between certain factors and Se BCF. As a result, predictive models were developed for soil Se, rice grain Se concentration, and Se BCF.ConclusionsThis study contributes valuable insights to inform policy-making for Se-enriched food production and to ensure regional nutritional equilibrium. Caution is recommended in areas with excessive Se levels to prevent potential poisoning risks.

Dependency of Long-Term Soil Quality Controls on Summer Fallow Tillage and Soil Layers for Dryland Winter Wheat in Loess Plateau

The capacity for winter wheat to produce sufficient yield may be influenced by soil tillage practices and soil quality. However, determining how to quantify the impact of long-term tillage on soil quality is crucial. Here, we address this issue by comparing soil properties and wheat yield under four tillage systems during summer fallow in the Loess Plateau. Twenty-two soil properties were explored to estimate soil quality. Results showed that a rotational tillage (PT/ST) during summer fallow decreased soil bulk density (ρb) and improved soil gravimetric water content (θg), soil organic carbon (SOC), soil capillary porosity (Pc), and total porosity (Pt) in 0–50 cm soil layers. A minimum dataset (MDS) of thirteen indicators was selected to calculate soil quality index (SQI). Treatment of PT/ST had higher SQI value in soil layers of 0–10 cm and 20–50 cm, and PT/ST showed a significant increase in yield since the third year. No tillage (NT) during summer fallow decreased soil physical and chemical indicators, thus decreasing soil quality. These findings suggest that a rotation tillage of PT/ST during summer fallow could enhance soil chemical and biological properties concurrently, and PT/ST may provide a promising management strategy to sustain soil quality and grain yield for dryland winter wheat in the Loess Plateau.

Thermo‐hydro‐mechanical coupled material point method for modeling freezing and thawing of porous media

AbstractClimate warming accelerates permafrost thawing, causing warming‐driven disasters like ground collapse and retrogressive thaw slump (RTS). These phenomena, involving intricate multiphysics interactions, phase transitions, nonlinear mechanical responses, and fluid‐like deformations, and pose increasing risks to geo‐infrastructures in cold regions. This study develops a thermo‐hydro‐mechanical (THM) coupled single‐point three‐phase material point method (MPM) to simulate the time‐dependent phase transition and large deformation behavior arising from the thawing or freezing of ice/water in porous media. The mathematical framework is established based on the multiphase mixture theory in which the ice phase is treated as a solid constituent playing the role of skeleton together with soil grains. The additional strength due to ice cementation is characterized via an ice saturation‐dependent Mohr–Coulomb model. The coupled formulations are solved using a fractional‐step‐based semi‐implicit integration algorithm, which can offer both satisfactory numerical stability and computational efficiency when dealing with nearly incompressible fluids and extremely low permeability conditions in frozen porous media. Two hydro‐thermal coupling cases, that is, frozen inclusion thaw and Talik closure/opening, are first benchmarked to show the method can correctly simulate both conduction‐ and convection‐dominated thermal regimes in frozen porous systems. The fully THM responses are further validated by simulating a 1D thaw consolidation and a 2D rock freezing example. Good agreements with experimental results are achieved, and the impact of hydro‐thermal variations on the mechanical responses, including thaw settlement and frost heave, are successfully captured. Finally, the predictive capability of the multiphysics MPM framework in simulating thawing‐triggered large deformation and failure is demonstrated by modeling an RTS and the settlement of a strip footing on thawing ground.

Influence of Simulated Erosion on Soil Properties and Maize Yield in the Southern Guinea Savanah Zone of Nigeria II

Aims: Long-term studies have been launched to assess the influence of artificial topsoil loss and its effects on soil properties and grain yield of cultivated maize. Place and Duration of Study: The study was conducted during the 2016 to 2019 agricultural seasons at the Federal University of Agriculture in Makurdi, Nigeria. Methodology: Three geo- referenced sites within the Federal University of Agriculture Makurdi, Nigeria namely: Site 1, Site_2 and Site_3 was used for the experiment. Erosion levels were established in June 2016 only by the incremental removal of topsoil at various depths. The study of crop productivity using simulated erosion was carried out using Randomized Complete Block Design (RCBD) with desurfaced soil depths of 0cm (control), 5cm, 10cm, 15cm and 20cm as treatments. One profile pit was also dug in each of the three sites for soil characterization and soil type establishment. Data collected on soil physical and chemical properties as well as crop growth parameters and grain yield was subjected to Analysis of Variance (ANOVA) using R core Statistical Software. Results: The study revealed that the soils of the three sites were classified as Kandic Paleustepts for Site_1, Typic Plinthustalfs for Site_2 and Typic Hapluderts for Site_3. These has brrn reported in drtail in paper I. In comparison with the 0cm (control), maize grain yield was reduced by 7%, 89%, 100% and 100% at Site_1, 5%, 64%, 82% and 85% at Site_2 and 6%, 71%, 82% and 92% at Site_3 for the 5cm, 10cm, 15cm and 20cm topsoil depth removal respectively. The topsoil loss greatly lowered the grain yield of maize. We report the effects of topsoil loss on crop productivity for two years.

Changes in Soil Physical Properties and Soybean Productivity under Preparatory Tillage Systems in Virgin Vertisols of Central India

Preparatory tillage, undoubtedly, is one of the most crucial practices that alter soil physical attributes and also affect crop growth and yield. In this sense, this experiment was designed to evaluate the effect of various preparatory tillage systems on soil physical properties and soybean productivity thereby find out a suitable tillage combination for vertisol of Vidarbha region of central India. The experiment was laid out in a randomized block design with eight tillage treatments and three replicates. Experimental results revealed that soil physical properties and productivity of soybean differed significantly under different preparatory tillage system and zero tillage. Further data revealed that conventional tillage treatment T8 (1ploughing + 2 tyne harrow + blade harrow) and T7 (1 Ploughing + 1 Tyne Harrow + 1 Rotavator) significantly improved the soil physical properties (infiltration rate, bulk density, porosity, soil moisture content) and grain yield (2378 and 2268 kg ha-1, respectively). Moreover zero tillage treatment T1 and shallow tillage treatments (1Blade Harrow + 1Rotavator and 1Tyne Harrow + 1 Rotavator) did not show any significant improvement in soil physical properties and grain yield of soybean.

Coupling Coordination Evaluation of Water and Soil Resource Matching and Grain Production, and Analysis of Obstacle Factors in a Typical Black Soil Region of Northeast China

Coupling Coordination Evaluation of Water and Soil Resource Matching and Grain Production, and Analysis of Obstacle Factors in a Typical Black Soil Region of Northeast China

Influence of Simulated Erosion on Soil Properties and Maize Yield in the Southern Guinea Savanah Zone of Nigeria I

Long term studies were initiated to study topsoil loss and its effects on soil properties and crop yield. This study was conducted during the 2016 through 2019 cropping seasons to assess the influence of artificial topsoil loss on soil properties and grain yield of maize. Three geo- referenced sites within the Federal University of Agriculture Makurdi, Nigeria namely: Site 1, Site_2 and Site_3 were used for the experiment. Erosion levels were established in June 2016 only by the incremental removal of topsoil at various depths. The study of crop productivity using simulated erosion was conducted using Randomized Complete Block Design (RCBD) with desurfaced soil depths of 0cm (control), 5cm, 10cm, 15cm and 20cm as treatments. One profile pit was also dug in each of the three sites for soil characterization and soil type establishment. Data collected on soil physical and chemical properties as well as crop growth parameters and grain yield were subjected to Analysis of Variance (ANOVA) using R Statistical Software. Results of the study showed that the soils of the three sites were classified as Kandic Paleustepts for Site_1, Typic Plinthustalfs for Site_2 and Typic Hapluderts for Site_3. We report the effects of topsoil loss on soil characteristics in this paper for two years only.

Validated simulation of a long-term cropping experiment reveals a pathway for improved productivity

Long-term farming system experiments with comprehensive soil, plant and meteorological data combined with well-validated dynamic farming system models are a powerful combination to evaluate the production and environmental implications of novel innovations in agriculture. A current deficiency is the lack of adequate comprehensive validations for long term crop sequences that capture the dynamics of soil and crop responses without resetting soil conditions, especially for soil mineral nitrogen (Min-N). This reduces confidence in the outcome of scenario analyses for proposed improvements in productivity and sustainability given the central role played by nitrogen (N) dynamics in both processes. We used data from a 30-year long-term experiment (LTE) to validate the APSIM model and achieved excellent predictions for soil and crop responses including the dynamics of Min-N without resetting. A critical step was to ensure that the parameters required for the pools of soil organic matter matched those measured at the site over the full rooting depth (1.6 m) rather than limiting measured values to surface layers and relying on default parameters in deeper layers. In subsequent scenario analyses of agronomic innovations including fallow weed control, earlier sowing and improved N fertiliser strategies, the validated model predicted potential increases in average annual productivity of 1.2 t ha-1 (30%), WUE of 2.0 kg ha-1 mm-1 (30%) and NUE of 13 kg kg-1 (21%) and reductions in average annual N leaching of 8 kg N ha-1 (-33%) and soil organic matter loss of 3.1 t ha-1 (31%) (0–10 cm) could be achieved with specific combinations of synergistic innovations previously investigated separately in shorter-term experiments. Our study represents a rare case of model validation capturing the dynamics of soil water, Min-N, biomass and grain yield in a long-term diverse crop sequence to provide confidence in scenario analyses of production and environmental consequences of agronomic innovations. LTEs provide a valuable resource for such validation, while conclusions drawn from simulation studies that lack comprehensive validation must be considered with caution.

The effect on the carbon footprint of the rice-wheat system of substituting chemical fertilizers by pig manure: The results of a field experiment

Livestock manure is widely recycled to enhance intensive agricultural production. Nevertheless, the environmental and agronomic benefits of liquid manure, such as biogas slurry, have rarely been comprehensively evaluated. To boost food production while maintaining environmental sustainability, a field experiment was performed to assess the effects of solid and liquid manure substitution for chemical fertilizer on direct greenhouse gas (GHG) emissions, soil organic carbon (SOC), grain yield, and carbon footprints (CF) in a rice-wheat system. The treatments involved only chemical fertilizer (NPK), 50 % NPK + 50 % pig manure (50 % PM), 100 % pig manure (100%PM), 50 % NPK + 50 % biogas slurry from PM (50 % PS), and 100 % biogas slurry from PM (100 % PS) in the circumstances of equal nitrogen fertilization. The results showed that rice CH4 emissions dominated the direct GHG emissions, and followed the order of 100%PM > 50%PM > 50%PS = NPK = 100%PS on average of three years. The 100%PM had the highest area-scaled CF with 11.84 Mg CO2-eq ha−1 due to high CH4 emissions and carbon emissions from pig manure production and compost indirectly without considering the changes in SOC stock. Meanwhile, 100%PM significantly increased SOC stock at 0–30 cm depth by 49.1 %, 11.8 %, 44.8 %, and 56.5 % compared with NPK, 50%PM, 50%PS, and 100%PS, respectively (P < 0.05). Notably, 100 % PM had the lowest area-scaled CF with 0.99 Mg CO2-eq ha−1 when considering the changes in SOC stock, followed by 50%PM. The 50%PM significantly increased the annual grain yield of rice and wheat from 2010 to 2018, with an average of 4.9 %, 4.5 %, and 5.7 % compared with NPK, 100%PM, and 100%PS, respectively (P < 0.05). Overall, although there was a trade-off between SOC sequestration and CH4 emissions under pig manure, pig manure substitution for chemical fertilizer significantly decreased yield-scaled CF, followed by biogas slurry substitution relative to NPK (P < 0.05). Thus, pig manure substitution for chemical fertilizer is recommended for environmental and yield benefits simultaneously considering the whole chain of production process in a rice-wheat system. In future, strategic fertilizer management based on PM and PS could potentially offer a sustainable solution to mitigate the trade-off and sustain the respective benefits of PM (i.e. SOC and grain yield) and PS (i.e. CH4 emissions).